1. Field of the Invention
The present invention relates to a spacer for a linear transmission apparatus, and more particularly to a spacer for cross rollers, which can make the roller move stably and can effectively reduce the contact area between the spacer and the roller, and also have a stable positioning function.
2. Description of the Prior Art
Since linear transmission products are being applied more and more widely in the modern industry, various linear transmission mechanisms have widely come into human life, manufacturing factory and high science and technology instruments, such as linear guideway, ball screw, and the like. Particularly in a large-scale precision mechanism are usually installed various large and small ball screws or linear guideway systems. Although the technology for linear transmission element is developing fast, consumers still need the technology to be improved uninterruptedly. Therefore, there are still some problems to be solved. And this desire for constant improvement of technology is particular strong in many high precision mechanism-manufacturing fields that require comparative stability and quiet. Hence, the existing linear mechanism still has some technological blind spots to be improved.
The spacer of the existing linear guideway has become the key research project of the related field, and since the spacer of the linear guideway is located between the rolling balls or the rollers, the spacer also is one of the key factors influencing the operation and the noise of the linear guideway. Therefore, the following different spacer products appear on the market:
As shown in FIG. 1, which shows spacers 11 used between the rollers 10, each of the spacers 11 has an arc contact surface for mating with the rollers 10, a chain 12 is arranged on a side of the respective spacers 11 for jointing the spacers together, and the spacers 11 prevent the generation of impact and noise between the rollers 10. However, this conventional spacer structure is impractical because of the following reasons:
First, the chain 12 on the side of the spacers 11 not only will probably affect the operation, but also will substantially increase the friction of the respective components.
Second, the conventional spacers 11 each has an arc contact surface for mating with the rollers 10, and the arc contact surface serves to contact the rolling surface 101 of the rollers 10, therefore, arc contact surface of the spacers 11 will produce an overlarge abrasion with respect to the rollers 10, adversely affecting the work efficiency of the linear system.
FIG. 2 shows another type spacer 14 used between rolling balls 13, the spacer 14 also has an arc contact surface 141 for contacting the rolling balls 13, and a chain 15 is arranged at a side of the respective spacers 14 for jointing them together. The spacers 14 prevent the generation of impact and noise between the rolling balls 13. However, this conventional spacer structure is also impractical because of the following reasons:
First, the chain 15 at the side of the spacers 14 not only will probably affect the operation, but also will substantially increase the friction of the respective components.
Second, this conventional spacer 14 has the arc contact surface 141 for contacting the rolling balls 13, therefore, arc contact surface of the spacer 14 will produce an overlarge abrasion with respect to the rolling balls 13, adversely affecting the work efficiency of the linear system.
Hence, with the popularization of the linear transmission application, the demand of solving the aforementioned problems is becoming more and more urgent, and manufacturing a spacer structure with less friction waste and high operation stability has become the most important selling point that the manufactures are striving for. Therefore, another spacer product was developed, as shown in FIG. 3, which is disclosed by U.S. Pat. No. 4,687,345.
This conventional spacer is used between cross rollers 16, and the spacer 17 is made by ejection molding and is arranged on the rolling surface 161 of the cross rollers 16. The spacer 17 has an arc-shaped contact surface 171 that can closely connect the rolling surface 161 of the cross rollers 16, hence, this conventional spacer structure can provide a stable positioning and anti-impact effect without the need of chain. However, it still has the following problems:
Due to the spacer 17 has an arc-shaped contact surface 171 that closely contacts the rolling surface 161 of the cross rollers 16, the friction waste caused by the arc-shaped contact surface 171 and the rolling surface 161 of the rollers 16 will be increased substantially. Although this spacer 17 maintains the operational stability, it will decrease the operation efficiency.
To solve the aforementioned problems, the inventor of this invention, on the basis of the accumulated experience and skills associated with the linear transmission field, develops a brand new spacer structure for cross rollers.